Hi All,
Some UM2 users are reporting under-extrusion problems, did you already tested your printer extrusion rates? You can download the *extrusion test here and should be printed at 230ºC
Should be interesting to know if this is a widespread problem or just a few isolated problems
Please post your results this can help you and others
Thanks
===
No problem: gr5, Waldorf, Takei, illuminarti, Skint, Shurik, IRobertI (@1.5A), Rabanwin, MostlyAtomicBob(@teflon coupler), braddock(@new bowden tube), CanadaDrones(@friction free spool), Arska, colorfabb(@loosening the 4 screws on the print head), Pikey, Stuart838, Nicolinux(@new printer), Didier_Klein, WoofysPlace (new nozzle), Ju1050, tomkooij, Calimero, ProfePaco
problem: MostlyAtomicBob, NicoLinux, Woofysplace, IRobertI, braddock, CanadaDrones, Geeks, colofabb, Shafe, Das_ENGINER
*Many thanks to illuminarti, it was him who made the extrusion test
illuminarti edit: For context, here's the link to the original posting of the test piece.

That's all true. It should behave identically.
It puts the same stress but in less time which means less heat and less bended filament to deal.
I agree the tests seems a bit stupid unless somebody tell that could print at 10-12mm3/s (200%speed) and can´t go over 6 or 7mm3/s with 100%speed

Hi Guys,
Did you Guys tryed to print the extrusion test at 200% speed? (twice the speed you will reach 12mm3/s at 6mm3/s band)
please post your findings, should be interesting to observe if underextrusion occurs in same rate as 100% tests. If someone passes the test at 200% speed and fails the 100% speed test this could indicate bended filament problems, fricion problems, heat problems, etc
Print more than one to get more consistent data
If the test fails you can repeat the test with @1,5A also

Well that's a shame...
The cable chain should move without any difficulty. I sanded my cable chain and he moves very smoothly and doesn´t put angular stress on the printer bed. Maybe one last thing to try before you give up
edit: Well I Did, knock on wood 3 times, I hope that can help you :mrgreen:
Hurray!! The cable chain stays!!

No, it's not! Did you already checked if you can pull more cable?
If you feel confortable to disassemble your printer, you can remove the stepper motors lid and the pcboard cover, then check if you have enough cable there. A shorter temp probe can be difficult to extend but I don't think that ultimaker is messing around with that either so if the bed wiring is too small, you can easily change it. take some photos to the wiring connections and then when you have to reassemble everything you can confirm with the pics
it's better. if you don´t have more cable to pull, I think it's not worth the effort to change the bed wiring, just because of one link only. the cable has plenty of room so I guess it's ok
Cheers

My temperature limit for PLA is 245ºC, higher temps and a few hours later I have to dissassemble the nozzle to clean the burned plastic. I noticed this with gold filament and can be a little different with other filaments. Today I tested transparent PLA and it seems that 230ºC is to hot, next print will be with PLA transparent at 220ºC (30mm/s, 0.1mm layer)

I am starting to like that advanced member thing. Farm animals it means there is fresh milk, bacon and eggs and maybe some nice country girls....
the voyage across the desert it's just stupid, since after cross the desert I will need more than a few beers and Ian will get a lot of trouble to get all the necessary beer to fill a thirsty camel.
I think I prefer to be a newbie and be seated watching my UM2 printing with a beer in my hand

yeah... wd-40 can help but will not fix your printer... so... now is becoming very interesting, after excluding the normal under extrusion little devils it seems that you have a bigger evil. Half empty spools can cause problems too but i do not think that is your problem it seems to me that your printer had problems since day one.
I think if it was the power supply you would experience more problems and they shouldn't be only "skip" steps related.
If you can exclude:
nozzle (hole diameter and clogs)
teflon coupler
3rd fan
bowden tube
material feeder stepper motor angle (a stupid nut that pushes the stepper motor)
knurled wheel screw tightening
too tight material feeder
spool friction
stock filament guide friction
filament bends
nozzle temperature variations
too tight bed calibration
correct assembly of the head
increase the current to 1.5A
?
Next suspects are:
stepper motor
board

Another thought...
What about the 3rd fan? It seems to me that his function is to cool the teflon coupler!? right? ... Is your 3rd fan always spinning with the same intensity? is well fitted? pushing air in the right direction?
Perhaps you can measure the air flow with an digital anemometer....
What are the consequences if the 3rd fan stops? is possible to achieve the higher rates of extrusion with the 3rd fan stopped?
I think illuminarti had problems in the past with the 3rd fan and probably knows the effects of a faulty fan. Can a too hot teflon coupler expand and generate more friction in to the filament?

Hi Schafe,
Damn I was really convinced that your problem was a dirty nozzle.
It's interessant to observe the numbers It seems that something deteriorates with time, hence I have thought it could be related to a clogged nozzle given the high extrusion temperatures used and the apparent increase of deterioration
2 X 10 - perfection
2 X 9.5 - had a small error in the 10 ring
2 X 9
2 X 8
1 X 7
2 X 6
2 X 5.5 - a small error in the 6 ring
5 X 5
2 X 4.5
4 X 4
4 X 3.5
10 X 3
6 X 2.5 - errors started in the 3 ring
I do not know what else to suggest to check, perhaps using the excellenthttp://umforum.ultimaker.com/index.php?/topic/3976-almost-always-missing-layers-underextruding/page-28#entry39843 and use it as a sort of checklist!? So far what have you checked/changed in your printer?

:shock: :eek: :lol:
I do not hate you Robert, or anyone in this forum. I do not want to be special because i am not. thanks for the crown, there were other more qualified candidates to receive this trophy, but I'll accept it with humility and dignity.
From now on I will dedicate myself only to the noblest posts and threads

I am sorry can´t comment on that... I am just a member, do not want to disrespect any moderator. (especially my favorite one)
However I never saw any new user confused with this and although there are bigger things to worry at the moment somebody is spending time on minor things...
Well, the important thing here is to keep this thread on first page and this way we can help newbies, members, moderators and Ultimakers
for the users with less sense of humor, I want them to say that I'm just kidding, it does not make sense to became an advanced member after 30 posts.